Stephan Bonnar's journey to Saturday night's clash with Anderson Silva at UFC 153 could have come straight from the script of a Rocky movie, writes Simon Head

A matter of weeks ago the amiable 35-year-old was contemplating retirement from the sport, believing his chance to feature in big-name fights had ebbed away. Now, after receiving a phone call a little over three weeks ago, he's set to take on the best fighter in the world.

Despite never being involved in a UFC world title bout in his career, Bonnar is one of the most significant fighters in the company's history.

His three-round war with Forrest Griffin in the finale of the UFC's first-ever season of their groundbreaking reality show, The Ultimate Fighter, has been credited as one of the major reasons for MMA's breakthrough into the mainstream consciousness in the US, and is generally considered to be one of the greatest bouts in UFC history.

And now, after a UFC career spanning seven and a half years, the man known as "The American Psycho" will finally get his big moment.

His bout at UFC 153, against pound-for-pound great Anderson "The Spider" Silva, would be difficult enough with a full training camp. But as the bout was hastily arranged with around four weeks' notice, Bonnar has had significantly less preparation time than usual.

"My training camp for this fight is three weeks and two days," he explained.

"I'm fighting the pound-for-pound best fighter on the planet with one fourth the preparation I usually put into a training camp.

"That makes me nervous, that makes me a little scared. But at the same time that gives me less time to worry about it."

To make things even more difficult for Bonnar, he'll be fighting Silva in the Brazilian's back yard. More than 15,000 fans will pack the HSBC Arena in Rio. Virtually all of them will be cheering for Silva.

The Rocky reference has been mentioned in passing during the build-up as Bonnar has happily - and sometimes playfully - taken up the mantle of underdog during the pre-fight promos. In fact, the only thing we're missing is a Rocky-style training montage.

But while Rocky is a Hollywood story, a movie, a scripted tale, Bonnar's test is very real indeed and a fairytale ending looks a distant possibility.

Silva is undefeated in 13 fights in the UFC, finishing 11 of his opponents inside the distance. As the UFC's middleweight champion he's been virtually untouchable for five years and he's moved up to light heavyweight and produced two of the most spectacular performances of his career.

But despite the challenge awaiting him in Rio in Saturday night, Bonnar appears unruffled, unconcerned and completely at ease with the task in hand.

The bout, a light-heavyweight contest, has no belt attached to it and, with the bookies rating him as a 8-1 underdog in a two-horse race, Bonnar says the pressure is all on his opponent.

"It's in his back yard, he's the huge favourite, he's the hero, he's the best pound-for-pound guy. I'm the guy who's supposed to go in there and lose."

But Bonnar has no intention of simply turning up to be a "tomato can" for Silva to knock over. Far from it. He plans on producing the biggest upset ever seen inside the Octagon and he believes everything is in place for him to shock the world on Saturday night.